Behavioral and Neuroendocrine Interactions in Affiliation

(To appear in R. W. Sussman and R. Cloniger (eds.) Origins of Altruism and Cooperation 6 Elsevier) 7 8 Affiliations take many forms in the social relationships of both human and nonhuman 9 primates. Which relationships are most important will vary as a function of the social structure 10 and breeding system that is typical of a species and will also vary with life history stages within a 11 species. For example in species where males disperse and females remain, it is likely that the 12 primary relationships (due to both genetic relatedness and social experience) will be between 13 female kin with both mother-offspring and sister-sister relationships having a high priority. In 14 species where females disperse and males remain there will be strong affiliation between 15 brothers as well as between mothers and offspring. In pair bonded biparental and cooperatively 16 breeding species, there is a strong affiliation or attachment between pair mates and between 17 infants and their primary caregiver. For example, in experimental studies with biparental titi 18 monkeys (Callicebus moloch) Mendoza and Mason (1986) have shown that when given a choice 19 between mate and infant the parents will choose each other and when given a choice between 20 parents, infants will choose their fathers which have been the primary caregivers. In 21 cooperatively breeding species such as the cotton-top tamarin (Saguinus oedipus) where father 22 and older siblings provide substantial infant care through carrying and food transfers, infants 23 who have become independent will, when frightened, preferentially seek the individual (father or 24 older sibling) that had been most active in carrying and food transfers (Kostan and Snowdon, 25 2002). 26